[UI-library] Prevent errors on disabled setting or stats panel.

[timbotimbo]

Relevant components:

• Signalling server
• Frontend library
• Frontend UI library
• Matchmaker
• Platform scripts
• SFU

Problem statement:

You can disable the settings and stats panel when using the ui-library.

const application = new Application({
	stream,
	settingsPanelConfig: {
		isEnabled: false,
		visibilityButtonConfig: { creationMode: UIElementCreationMode.Disable }
	} ,
	statsPanelConfig: {
		isEnabled: false,
		visibilityButtonConfig: { creationMode: UIElementCreationMode.Disable }
	} 
});

However doing so might give you various errors because the settingsPanel or statsPanel variable will be undefined.

• If you only disable the settings panel, the stats button will break.
  The console shows an error as it tries this.settingsPanel.hide();.

• If you only disable the stats panel, you get the reverse with the settings button breaking.
• However the stats panel is also called repeatedly in other functions like
  onPlayerCount, onVideoInitialized and onStatsReceived.
  Although these don't seem to break anything visible to the user, they throw hundreds of console errors during a short stream.

Solution

Adding some ? operators on usage of this.settingsPanel and this.statsPanel to avoid throwing errors.

Documentation

N / A

Test Plan and Compatibility

Some additional null checks shouldn't break any compatibility or features.

The stats and settings button don't break anymore in manual testing.

Backporting

These errors show up starting with version 5.2 (which I use), but I'm making this pull request on master.
But because of code changes I'm not sure if a backport from master will fix all occurences in 5.2 and 5.3.

Please let me know If I need to make separate pull requests for other versions.

[Belchy06]

LGTM!

[lukehb]

Yep, that's a good idea. Code looks good to me. Lgtm.

[github-actions]

💔 Some backports could not be created

Status	Branch	Result
❌	UE5.2	Backport failed because of merge conflicts You might need to backport the following PRs to UE5.2: - Merge branch 'master' into patch-1 - merged in origin master
✅	UE5.3
✅	UE5.4

Note: Successful backport PRs will be merged automatically after passing CI.

Manual backport

To create the backport manually run:

backport --pr 392

Questions ?

Please refer to the Backport tool documentation and see the Github Action logs for details